Data Cruncher wrote:
>> And unlike you some people read the docs.
>>
>> Oracle offers other isolation levels too.
>> http://download-west.oracle.com/docs...t.htm#CNCPT621
>>
>> If you are going to bash something at least choose a valid point on
>> which to bash. One thing I find fascinating about some in this crowd
>> is the willingness to close their eyes and throw punches.
>>
>> Those of us who actually know Oracle throw them too. But ours are on
>> target.
>
> When I said SS/Informix offers other choice, it means
> that the developers has a choice to bypass CPU intensive
> versioning mechanism. Does Oracle offer a way to bypass
> check for block versioning and then fetch from UNDO segment.
> AFAIK - no. The only other choice they have is actually
> worse from concurrency point of view, like SERIALIZABLE.

No bypass for multiversioning with the standard isolation level.
But then Oracle gains functionality Informix hasn't had, except
as an option with Cheetah. Functionality has its cost.

The reverse question from the other side is ... having fun with
row and page locking and lock escalation?

In truth the cost of multiversioning is quite small as compared
with the cost of other functionality built in during the last
several versions which few of you know about because you don't
actually study the competition you just throw random punches in
the dark.
--
Daniel A. Morgan
University of Washington
damorgan@x.washington.edu (replace x with u to respond)